"The VOR is a beacon that sends out a signal that allows pilots to calculate their altitude as they approach an airport. It's what pilots relied on before the invention of the glide scope. [sic]"

"Guam airport has what is called a glidescope[sic], which is like a giant beam of light stretching upinto the sky from the airport, and the pilot simply followsthe beam all the way down to the runway."

"The typical commercial jetliner—at this point in its stage of development—is about as dependable as a toaster."

Malcolm Gladwell (in The Outliers)

If I trust Gladwell, the average life span of a toaster should be 1000 years, with 10 toast cycles per day so that they can become as dependable as airliners...